Calculating device



CALCULATING DEVICE Filed April s. 1924 lo zo Jo 4a 5o 5o zo :04o so 6D au su Patented Sept. 15, 1925.

UNITED STATES ROBERT T. FUBBISH, 0F LOCKPORT, NEW YORK.

GALCULATING DEVICE.

Application filed April 5,1924. 'serial Nu. 704,356.

chines and has for its principal object the'v provision of. a simple and( etlicient device for multiplying a plurality of numbers together and dividing their vproduct by" a third or fourth number.

A further object of my invention is to provide a machine withvwhich the computation of the amount of radiation required for' a building can be performed simply and eficiently without the need` of bearing vin mind the decimal point, thus avoiding a serious objection to the use of a slide. rule, and a further improvement of the present device over all slide rules consists in the fact that in the slide rules the divisions are Vof 'different ysizes and values necessitating nervous tension on the part of the operator to insure'correct reading whereasin the `de' vice here illustrated the divisions are uniform. l v

4At the present time the calculations of required radiation in a building are performed invariably by ahigh priced man and it seems absolutely essential that the work be so done dueto the choice of'the"K factor which varies vfrom .001 to about 2%. Even with the use A'of my calculating device it is 4essential that `the high priced engineer give the/values of the factor to the calculating machine operator, but with my machine a much lower paid employe can ligure out the dimensions of the varlous rooms and `with the correct K factors given by the heating engineer (who would also give notes as to special features) the lower paid and less valuable man could take the computer and make all the calculations with the least possible chance for error and where the checking system is used in this class of work the computor would doubly increase the sav ing. y

In the drawings, Figure 1 is a plan'view of my device. Flgure 2 -1s an edge view, I

'On the bedl() are mounted a pair of guides 11 and 12 for the slide 14, a, central guide 15 having beveled edges 16 and 17, `and a ledge 18, the top surface of which is flush with the top of the guides 12 and 15 so as to furnish a smooth support for the horizontal bar 20 which carries cleats 21 and 22 neatly fitting the sides 16 and 17 of the guide 15, as best seen in the edge view, Fig. 2, this arrangement maintaining the bar 20 at all. times at right angles to the slide 14. K

At the top of the base or bed 10 I provide a cross piece 25 slotted as at 26 to permit of passage of the cleats 21 and 22 and preferably the guide 15 is likewise extended through .the slot ending flush with the top edgeof the board 10 and cross piece 25'. The edge frame has no other function than to improve the general looks of the device and its top is Hush with the upper surfaces of the 1,553,633 'PATENT OFFICE.

slide'14, the cross piece 25 and the sliding horizontal' bar 20.

The slide 14 moves vertically, that is, ,to-

ward and away from the operator but may be' held in any desired position by means of a fastening means 30 here shown as a friction screw extending through the slide 14 and adapted to engage the bed 10 but which obviously may be of'any other desired form its sole function being to lock the slide 14 with respect to the base 10 and the guides 11 and 12. The horizontal or cross bar 20,

while free to slide up and down on the guide 15, is provided with a locking device 32 here shown as a simple bolt which engages a small kerf or slot 33 in the slide 14 so that when the bolt 32 is shot the slides 14 and 20 will move together on their guides.

The vertical slide 14 carries two scales A and A both for use with the factor K which is a value found by experience and which may be obtained from tables. This factor K is, for example, for a -ireproof floor, .10; for a brick wall from .19 for a 27 -inch wall to .'37 for a 9-inch wall, while a sheet of lplate-glass would have a factor of 1 and a lthe Fahrenheit scale.

A u ed with the main scale C also on the cross piece 25 has numerals which denote square feet and not cubic feet. In practice no diiculty -or confusion has been noted since the two nearest scales are used together and the two farthest scales are used together and furthermore the vast difference in numbers prevents any confusion of A"and C with A and C. l

On the barl is a scale E the numerals of which denote the difference .in degrees on Throughout this description the figures are given as on the computingdevice as actually made but it should be borne in mind that the invention is not limited to a heat calculating mechanism and that the values on the three scales'may be anything desired depending upon the normal values ofthe elements of the formula A x Bl x C divided by D equals E.

A long transparent rule 40 having a central reference line F is pivoted to the slide 14 in such a manner that its pivotal axis lies at the junction of a line drawn through the zero of the A scale perpendicular to the edge of the, slide 14 and a line drawn through the zeros of scale C', C and E. The pivot of the rule 40 is so arranged above the surface of the slide 14 that the lower surface of the rule will lie. in the same lane as the upper surfaces of the scales A, and E. 4The ref erence line F may -be placed on the rule in any desired manner but I prefer the well known scheme of scribing a fine line on the top of the rule and filling the tiny groove with india ink. y

The operation of the device may be readily understood from a simple example. We desire to obtain the amountof heating surface required for a bath room for example. This room and all other rooms in the house will have the same values for difference in temperature, B of the formula, and for the number of British thermal units given of per foot per hour, this value being D of the formula. We will assume that the lowest outside temperature is zero and the desired inside temperature 70 F. giving a temperature difference of 70 and we will assume that in the design of the heating means contemplated 200 B. t. u. are given off per hour per foot. so that its line is inv registry with unity on the A scale and the bolt is then shot so that the two slides move together. The line F of the rule is now moved over the 70 graduation on scale E and is held there by the index finger for example while the slide 14 is moved down or up as the case may be until the line F is over the chosenvalue of D which is found on the C scale. The slide l14 is now locked by means of the screw 30 and the bar D released and the device is in condition for finding the radiation required for any given number of square or cubic feet at any chosen factor.

We will assume the bath room has 480 cubic feet and that the factor for the'volume is .02. The scale E is brought into registry with .02 on the A scale, the rule is moved until i-t is over 400 on the C scale and the answer in feet of radiating surface is found on the E scale as between 2 and 3. For the walls of the same room we will assume they figure but 112 square feet and the factor for walls of the kind had is .29. The scale E is brought into registry with .29 on scale A and the rule moved to 112 on scale C the an-l swer as before being found on scale E as 11. The glass, ceiling and floor are separately calculated in the same manner and the total of the different multiplications give the total amount of the radiation required for the room.

What I claim is:

In a device of the character described, a fixed scale, a sliding scale constantly parallel thereto, a sliding scale constantly perpendicular to each of said scales and a rule sweeping over said parallel scales.

ROBERT T. FURBISH.

The horizontal bar 20 is moved 

